This invention relates to thermal insulation, and particularly to improvements in gas impervious pouch structure for containing a porous mass of thermal insulation and a charge of gas having a coefficient of thermal conductivity lower than that of air.
Pouch structures containing insulation and gas as described have been found useful as insulation units for installation in the walls and doors of refrigerator cabinets. Such units both facilitate handling of the insulation and enhance performance of refrigerator cabinets and the like within which they are installed. These insulation units also have been found useful for other home appliances, such as, for example, freezers and water heaters, as well as for residential and commercial building structures.
Fibrous insulation comprising glass fibers or the like, in combination with an insulating gas such as difluorodichloromethane, commonly known as F-12 refrigerant, and enclosed in pouch structures of materials that are both gas and moisture impervious, have been used. Pouch materials have comprised laminae of: Mylar (a polyester of ethylene glycol and terephthalic acid) and Saran (a vinyl and vinylidine chloride copolymer), as taught by U.S. Pat. Nos. 2,817,123 and 2,817,124; Saran and paper, as taught by U.S. Pat. No. 2,966,439; paper, polyethylene and Saran, as taught by U.S. Pat. No. 3,004,877; and Mylar and vapor deposited aluminum as taught by U.S. Pat. No. 2,863,179.
The hereinabove identified patents are believed material to the examination of this application, for reasons briefly stated, and it is a general objective of this invention to provide an insulative unit of the pouch enclosed type that affords improved handling and performance characteristics.